山药中尿囊素的高效液相色谱分析方法研究

建立了山药中尿囊素的高效液相色谱分析方法。样品用甲醇－水（９０：１０,Ｖ／Ｖ）提取,在氨基柱上进行高效液相色谱分析,紫外检测波长２２４ｎｍ,流动相为甲醇－水（８０：２０,Ｖ／Ｖ）,相对标准偏差为２．０％（ｎ＝５）,尿囊素的回收率为９８．８％（ｎ＝４）。     

尿囊素对玉米幼苗的生物效应

用盆栽试验方法,通过对玉米幼苗期生物学性状及核酸含量的测定,研究玉米经不同浓度尿囊素溶液浸种处理后的生长发育情况．结果表明,尿囊素处理的玉米发芽率、株高、根长、地上和地下部生物学产量及核酸含量等均比对照有不同程度的提高,其中１０(－６)ｍｏｌ／Ｌ尿囊素处理尤为明显．     

Radiostability of Allantoin by Using Electron Spin Resonance Spectroscopy

The radiosterilization potential and dosimetric feature of allantoin were investigated through the molecular degradations produced after ultraviolet and gamma irradiation using electron spin resonance, infrared, and ultraviolet spectroscopies and thermal measurement techniques (differential thermal analysis and the glass transition temperature). Although ultraviolet-irradiated allantoin presents no electron spin resonance signal, gamma irradiation exhibited an electron spin resonance signal of triplet appearance. Room temperature and high-temperature line intensity and spectrum area data and their variations with applied microwave power, storage time, annealing time, annealing temperature, and applied radiation dose were analyzed by assuming the production of two different types of radicals having different spectroscopic and decay characteristics. Based on its relatively stable nature toward gamma and ultraviolet radiations, it was concluded that allantoin itself and the products containing it can be sterilized by gamma and/or ultraviolet radiations without creating a great loss in its beneficial effects in the allowed radiosterilization dose limits.     

稀土固体超强酸SO_4~(2-)/TiO_2-La~(3+)催化合成尿囊素

尿囊素(1 脲基间二氮杂茂烷二酮—(2,4),allantoin)是一种两性化合物,可作为医药、化妆品、农业等化工原料中间体。通常用硝酸或过氧化氢氧化乙二醛生成乙醛酸后,再在酸催化下由乙醛酸与尿素缩合而成。但采用浓H2SO4、HNO3等作催化剂,产率偏低(<50%),选择性差,产品质量不好,同时设备腐蚀严重,污染环境。用SO2-4/MxOy型固体超强酸催化剂催化合成尿囊素[2 3],仍有产率偏低等不足之处。我们用La3+掺杂改性SO2-4/TiO2体系,合成了稀土固体超强酸催化剂SO2-4/TiO2 La3+,考察了合成尿囊素缩合反应的催化条件,在最适宜的反应条件下,催化…     

Proliferative and antioxidant activity of Symphytum officinale root extract

The root of Symphytum officinale L. is commonly used in folk medicine to promote the wound healing, reduce the inflammation and in the treatment of broken bones. The objective of our investigation was to analyse the extract from S. officinale in term of its antioxidant activity and the effect on cell viability and proliferation of human skin fibroblast (HSF). Moreover, the quantification of main phenolics and allantoin was conducted using HPLC–DAD method. Five compounds were found: rosmarinic, p-hydroxybenzoic, caffeic, chlorogenic and p-coumaric acid. DPPH, FRAP and TPC assay showed the high antioxidant activity of the extract. MTT test proved the stimulatory effect on cell metabolism and viability of HSF cells. Moreover, no changes in cytoskeleton structure and cells shape were observed. The obtained results indicate that non-toxic extract from S. officinale root has strong antioxidant potential and a beneficial effect on human skin fibroblasts.     

高效液相色谱法测定山药样品中尿囊素的含量

用薄层扫描方法确定了山药中尿囊素的提取条件;用高效液相色谱方法测定了山药中尿囊素的含量,考察了不同产地山药样品中尿囊素含量的差异.该法平均回收率为96.8%,相对标准偏差为4.0%.生长环境、气候等外界条件对山药中尿囊素含量有明显的影响,不同产地山药中尿囊素含量有明显差异.此高效液相色谱法用于山药中尿囊素的含量测定,灵敏度高,重现性好,可供山药质量标准研究参考使用.     

2,4-二酮-5-咪唑烷基尿的~(15)N和~(13)C核磁共振研究

本实验测定了2.4-二酮-5-咪唑烷基尿的~(15)N和~(13)C NMR谱并确认了谱线归属。根据化学位移及其在脱质子化过程中的变化,讨论了化合物的互变异构平衡及立体构型的转化问题。结果表明,在溶液中此化合物以酮式结构(A)为主要构型。     

乙醛酸衍生物的研究进展

乙醛酸衍生物广泛用于作医药、农药、香料、化妆品和染料的中间体,此文综述和评论这些衍生物研究的进展,包括乙醛酸和尿囊素、酚的衍生物、扁桃酸、香兰素、胡椒醛、对羟基苯乙酸、对羟基苯甘氨酸、取代丁烯酸等.     

非催化条件下合成尿囊素

以尿素和乙醛酸为原料,在无催化剂存在的条件下,合成了尿囊素。优化反应条件为:乙醛酸30 mmol,n(乙醛酸)∶n(尿素)=1.0∶3.0,于60℃反应3 h,产率60.3%,纯度98.0%。     

反相高效液相色谱法同时测定化妆品中的尿囊素和泛醇

采用反相高效液相色谱法同时分离测定化妆品中的尿囊素和泛醇。用YWG C 18 柱(250 mm×4.6 mm i.d., 10 μm)分离,以0.02 mol/L 磷酸二氢钾-甲醇(体积比为90∶10)为流动相,检测波长210 nm。尿囊素的最低检测量为8 ng,最低检测浓度为0.4 mg/L ;泛醇的最低检测量为32 ng,最低检测浓度为1.6 mg/L 。尿囊素和泛醇的回收率分别为82.03%～103.80%和95.50%～109.12%;选择唇膏等4个不同样品作了精密度实验,样品中目标组分含